1. Field of the Invention
The present invention relates to a data communication apparatus for use in communicating video and audio data, and in particular to a data communication apparatus such as a facsimile apparatus, having a memory which is used in common for temporarily storing video and audio data which have been received or are to be transmitted.
2. Description of the Related Art
In the prior art, as described for example in Japanese Patent Laid-open No. 3-36868, a data communication apparatus is known whereby a single memory is used in common for storing video data and audio data that have been received or are to be transmitted. Diagram (a) of FIG. 1 illustrates the memory arrangement of such a prior art apparatus. The memory space is divided into a video region A and an audio region B which are respectively reserved for temporarily storing video and audio data. The user of the apparatus can establish a boundary address X in accordance with the memory usage condition, whereby the respective sizes of the video region A and audio region B can be increased or decreased.
For example in the case of a user who does not use an unattended telephone message recording function with such an apparatus, the boundary address X could be set to the highest address value of the memory, so that the entire memory space is allocated to the video region A. Conversely in the case of a user who does not use video data sending and receiving (e.g. facsimile) functions with such an apparatus, but who makes frequent use of an unattended telephone message recording function, the boundary address X can be set as the lowest address of the memory, so that the entire memory space is allocated as the audio region B.
It should be understood that the term xe2x80x9crecordingxe2x80x9d as used herein refers to the storage of an audio telephone message in a memory, after conversion to digital data.
When the video region A is completely empty, and the memory is to be used for video data sending or receiving operations, then the video data of document pages which have been received or document pages which are to be transmitted are thereafter stored in a set of addresses successively extending from the lowest address number of the memory. If at the stage when such video data have not yet been outputted from the memory it becomes necessary to store new video data (i.e. for document pages which have been received or are to be transmitted) then the new data are stored in addresses which successively increase from the highest one of the addresses in which video data have already been stored.
If the audio region B is completely empty and audio data are received, then that data are stored at addresses which successively extend from the lowest address of the audio region B. When audio data are received thereafter, the new data are stored in addresses which successively increase following the highest one of the addresses in which audio data have already been stored.
Diagram (b) of FIG. 1 illustrates a condition in which sets of video data a1 and a2, and the set of audio data b1 have been stored in the memory. The memory control section of such a data communication apparatus is provided with a memory management table for use in managing the utilization of the memory. The management information consists of the initial address and final address of each set of video data which have been stored in the memory (or, for each set of video data, the initial address and the number of bytes constituting the video data), flags for distinguishing different types of data (i.e. video or audio), the amount of usable storage capacity of the memory which remains available for storing video data and audio data, and the boundary address X. Each of these items of memory management information is registered in the memory management table. When data stored in the memory are outputted (i.e. to be transmitted, recorded or reproduced), the memory management information relating to that data are deleted from the memory management table. Thus the amount of remaining memory capacity, as registered in the management table, is increased by an amount corresponding to the storage range of the outputted data. The memory control section can thus manage memory write and read operations by looking up the management table.
However with such a prior art configuration, the following problems arise:
(a) Even if the user attempts to set the boundary address X at an optimum position with regard to the usage conditions of the apparatus, problems arise because there is no clearly defined target value for setting the boundary address. Moreover there is no simple way for the user to confirm that the position which has been set (within the memory space) for the boundary address is appropriate.
(b) When data transmission or receiving is being executed using the memory, then in order to prevent communications from being interrupted as a result of insufficient memory space, it would be convenient for the user to be able to confirm the amount of remaining memory capacity. However with such a prior art type of data communication apparatus, the user is not provided with information to enable the remaining memory capacity to be easily confirmed.
Moreover as shown in diagram (c) of FIG. 1, in a case in which the video region A has become insufficient, but there is some available memory capacity remaining in the audio region B, it is not possible to obtain additional video data storage capacity by going beyond the memory region A.
It is an objective of the present invention to provide a data communication apparatus having a memory which is used in common for storing video data and audio data, whereby setting of a boundary address at an appropriate position for defining a video region and an audio region within the memory and also confirmation of amounts of remaining memory capacity, can be easily performed, and further whereby the efficiency of utilization of the common memory can be improved by comparison with the prior art.
To achieve the above objectives, a data communication apparatus according to the invention converts an amount of memory space which can be used for storing video data into an equivalent number of standard document pages, and displays that number of pages. Similarly, an amount of space that can be used for storing audio data is displayed as an equivalent number of telephone calls, i.e. telephone messages. The user without specialized knowledge can thereby more readily understand the amounts of memory space when thus expressed as a number of pages and number of telephone calls, than would be the case if these amounts were displayed in the usual units of bytes or kilobytes.
More specifically the present invention provides, in a data communication apparatus including communication means for transmitting and receiving video data and audio data, the video data being derived from documents, a memory for storing at least video data and audio data received by the communication means, memory control means for executing management of utilization of the memory and for controlling data write and read operations of the memory, and data display means the improvement comprising display control means for controlling the data display means to display first memory capacity information representing an amount of capacity available in the memory for storing video data and second memory capacity information representing an amount of capacity available in the memory for storing audio data;
the display control means comprising means for expressing the first memory capacity information as a number of first data units, each of the first data units consisting of am amount of data corresponding to one standard document page, and for expressing the second memory capacity information as a number of second data units, each of the second data units consisting of an amount of data corresponding to one fixed-duration telephone message, and means for controlling the display means to display the number of first data units and the number of second data units.
With such an apparatus, the memory space of the memory can be divided into a video region which is reserved for storing video data and an audio region which is reserved for storing audio data, with a boundary between the video region and audio region being defined by a boundary address, with the first memory capacity information being an amount of capacity of the video region and the second memory capacity information being an amount of capacity of the audio region.
Moreover such an apparatus can further include means for establishing a boundary address setting mode of operation wherein one of a plurality of respectively different values of the boundary address can be selectively established by a user, and wherein the display means is controlled to display during the boundary address setting mode, for each of the plurality of boundary address values, a corresponding amount of capacity of the video region, expressed as a number of the units of document pages, and a corresponding amount of capacity of the audio region, expressed as a number of the units of telephone messages, the display means being further controlled to indicate the boundary address value which is currently selected.
Such an apparatus may also include means for establishing a residual capacity display mode of operation wherein an amount of capacity that is currently vacant in the video region is displayed in the units of standard document pages and an amount of capacity that is currently vacant in the audio region is displayed in the units of telephone messages.
In general, the units of telephone messages will respectively correspond to standard recording intervals for storing audio data in the memory, and the apparatus may further comprise means for establishing a recording interval setting mode of operation wherein one of a plurality of respectively different values of the standard recording intervals can be selectively established by a user, and wherein the display means is controlled by the display control means to display during the recording interval setting mode, in correspondence with each of the different standard recording interval values, a corresponding value of the second memory capacity information, expressed as a number of the units of telephone messages, and to display an indication of one the standard recording interval value which is currently selected.
Such an apparatus can alternatively be operated such that video data which are successively written into the memory are written into addresses which successively change in a direction from a first one of a highest address and a lowest address of the memory towards a second one of the highest and lowest addresses, and wherein audio data which are successively written into the memory are written into addresses which successively change in a direction from the second one of the highest and lowest addresses of the memory towards the first one of the highest and lowest addresses. In that case, since there is no fixed boundary between the video and audio storage regions, greater flexibility of memory utilization becomes possible.